Sensitized sheets provided with a screen



July 8, 1952 w. M. BusKEs ErAL 2,602,742

i SENSITIZED SHEETS PROVIDED WITH A SCREEN Filed oct. 24, 194e FIG-1 l I M. v l FG 3 6 la /6 f5 Patented July 8, 1952 2,602,742 sENsrrIzEn SHEETS PROVIDED WITH A SCREE Willem Marie Buskes,

Petrus Wilhelmus Sa Paulus Vallen, and Kar Velden, and Theodor-usY nders, Matheus Marinus el Maria Hutgens, Venlo,

Netherlands, asjsignors to Chemische Fabriek L. vander GrintemVenlo, Netherlands, a company of the Netherlands October 24,1946, Serial No. 705,310 Netherlands November 1, 1945 26 claims. (c1. 95-8) v Application l .'-Ill th This invention relates vided with a covering screen'to be used in the production of 'screen reex copies Ain theposi#- tive diazo processi.v

It is often vnecessary'for` the screen-pattern in such screenfcovered sheetsfparticularly those with a fine screen'structurato'be in closeproximity to the sensitized'layer, as for example, wit-h the use of diffused light in screen-refie'ctographyl In'such cases the screen-pattern calls for greater accuracyand covering than is obtained inv or" dinaryprinting technique, high printing,A deep printing and flat printing; While this accuracy and covering is obtained with certain types of photographically produced screen-patterns, these on the Whole are expensive and offer a very limited choice Aas to the substances capable of forming the covering portions (light'obstructing portions) of the screen-patterns.

This invention provides relatively inexpensive transparent light-sensitive sheets formed with an integral screen, for use in positive diazotype reflectography processes, which meet highV requirements. The screen'pattern of these sheets consists solelyv of portions thatl are substantially impervious to light to which the sensitized layer is sensitive, alternating with portions that are substantially entirely pervious to such light, i. e., Without intermediate graded` transitions.

According to" the `invention the. screened sensi- -tizedsheetsf arev so constituted jthat the screenpattern' is arranged in Vthe Aimmediate vicinity ofthe sensitized layer and that the substance constituting the covering (light-obstructing) portions of the screen is deposited rin cavities inthejsheet.l j 'f This permits of a wide vchoice in the selection of substances for the'covering portion, as a resultfof which,A particularly eifective screened sheets are possibleL-as will appear from theV examples; j*

In -one'embodiment vof `the invention, which provides the' desired 'close' contact between screen-pattern andv sensitized layer,"th'e cavities containingthe substances constitutingthe covering portions are formed inthe sensitized layer itself. This vconstruction `is specially Vadapted for use in screen-reflecto'graphy and is, generally speaking, cheap. The copyobtained-with Vsuch a sheethasv a relief surface which, providedY it possesses Ysuflicient neness of structure, has the advantages of a dull surface (bengless glossy andfbetter' suited to writing).

Onemethod of obtaining ajscreen pattern for'Y thejsensitized sheets, `according to this ivnven tion, is by producing, either sweeping or rubbing it off,l for example by means of a doctor blade. l i obtained by subjecting the sheet to the actionof a press or mould where the sheetisitself suf-f flcientlyplastic or becomes plastic e. guunder heat (by heating to a certain*temperature)f,'or" by casting it on suchk mould; the press or mould forming the Vcounterpart of the desired pattern (cavities) to be'produced in the sheet. .'As a ller, i. e. the covering substance for the cavities in this relief pattern, pigments, Vcolouring matters, mixtures with colouring matter, carbon j black, barite, zinc white and the like rnayjbejy employed. A covering substance `may also bev selected which does not absorb visible light jbut does absorb e. g. ultra-violet light, or the 'sub-j stance may be such that when subjected'to an I after-treatment, which the image formed on Y the sensitized layer normally undergoes,` it jloses itslv absorptive power or its covering power. Preferably the covering substance is so chosen that' it a diazotype layer wherein developmenty is effected by covering it with a thin layer ofthe developer, and in Whichthecavities are formed in the sensitized layer itself, 'while the covering substancejis soluble inthe after-treatmentliquid, e. g. the diazotype developer. 'It isfobvious'jthat the coveringV filler substance should be suitable as regardsk the sensitized layer, the thingslwith whichv it comes into contact during processing, the Yultimate image, etc. VThe substanceselectedf as ller shouldyof course, not lose itsf covering' power too quickly, e. g. vunder the influence of' moisture.

- If the coveringsubstance employed is not of such a nature that it can be removed byfd issolu-fl tion, for instance in an after-treatmentliquid;

it generally should be` removable after exposure,

in some other way. In some cases itsjrernova'l` in the' sheet itself or, where the sheet consists of morel thanmonef layer, in one of its component layers, a relief pate` tern of the desired screen yform Vandmin iilling the formed cavities of this pattern 'withthecovering substance and removing the excess of;` this substance by wiping it off, i. e., by doctoring,

This relief pattern may be aeoavea" It has now been found that certain of thesadifcultiesmay be obviatedby imparting such a degree of cohesion to the particles of the covering screen portions that it will be possible to remove the covering substances, rsubstantially in Care should' their entirety, from the cavities.

be taken in such a case that the attachment"v of the coherent screen portionsto, thefbcttom and sides of the cavities is not too'great.

The desired degree of cohesion between the particles can be obtained by usingl asuitable amount of a binding agent. A simple way to attain this is to mix, for instance, the paste of\ the covering substance in e. g. toluene (see EX- ample 3) with a substance like, rubber, in suchl aquantity that, after the toluene has evaporated,

the covering portionsform a more or less, sof t ,1 as it Werefsintered (caked), massin therca'viti'es,"

Thesefcoherent parts can.v readily be removed.

ifrom the cavities in a considerably cleaner yway bythe. method of Example 3 than when` the particles possess. little, if any cohesion.- It has been found that it is possible to select the bind.- ing agentand theamount of it in suchamanner that thecohering screen portions can be removed very simply, quite cleanly and evenin dry conf.

dition with'the aid of an adhesive surface, for

instance dry adhesive paperadhesive-'ribbonor the like; to effectthis, it is of course necessary,`

for the coherent screen portions to attach themselves adequately to the. adhesive surface' used. It is also possibleto provide the .cavities with coherent covering parts. by filling them with a. liquid and subsequently passing the foil under a doctor knife, the said liquidr being one which; upon solidifying or drying the `mass,. will form a coherentcoating (e. gl of. crystals).l possible to proceed according. to the methodofr Example 3 4and. thus obtain a filling withoutcohesion, followed by impregnation with a liquid required cohesion.

By repeating the filling and doctoring process. l more than once itisalso possible toarrange diiferent types of fillings `in, layers, one'on top. ofi Thus Ythe .bottommos't layer in con# the other.

.45 which, upon solidi-fyingor. drying, suppliestheY tact WiththebottomY of the' cavity may beonf 1 thatadheres .butrslightly thereto, Vwhereas.'theVv layer supplied-last (the top layer)v may be fone havinga greatadhesive power withrespectto.

the adhesivesurface to beapplied whenremov-f ing thecovering screen portions from the. 'sheet. l Provided one of the,layers.suppliedforex-A ample the last, is suciently pervious tothe Vactive A"60 muchtothe uncovered tops, this layer, ifdesired,

light' and provided it does not attach itself too.

need-notbe subjected. to alwiping off operation e. g. bythe action of adoctor knife; it will. then! form acoating extending also over. the. elevated parts between'the cavities'prope-r, thus impar-t; ing cohesionof-a covering screen portior'iwiththel adjacent covering screen portions.. This.. f: rrnf Y of the invention is particularly suitable for. 'the'f a mixture' constituting thecov'eringsulristance.` is applied to the surface of the skin onthedrum f so as to ll up thecavities therein.v `On l eaving removal of the screen with lthe aid of an.-ad-JY hesive surface, care being.y taken to ensureathatV the topmost layerY adheres sufficiently to the adhesive surface applied.

For lie-screening the sheet with the .aidoffanf adhesive surfaoe,the latter mustbe of. such.a, nature that the degree of adhesion of the screen 4 components to the sensitized sheet is smaller than their degree of adhesion to the adhesive surface. In this connectionit is lobserved that in respect of thismethod of screen-removal words Ylike adhesive surface, adhesive power and the like, are to be taken in a wide sense. Thus, the conception adhesive surface e. g. also includes a so-called vacuum surface or a combination of a vacuum and an adhesive surface.

Adhesive powerfor instance also comprises the magnetic force acting on screen portions consisting ofv iron or of a mixture containing a sufficient amount vof iron.

1 When yremovinga screen skin, dia-screening with theaid of an adhesive surface is of particular. vimportance when such screen skins are very thin and weak, i. e. when they have a weight or less than approximately 20 g. per m.2.

In many cases the screen can be removed mechanically. o v

The invention will'be` elucdated'withjreference tothe drawingsv and the examples..

In the accompanying drawings:

Fig 1 is a part sectional view showing asur'- face conguration for the drum of Fg.2.

Fig. 2 is a sectional diagramshowinga Ina-chine for the production of the sheet..V

Fig. 3 is a sectional view 'illustrating a serisrtizeolv sheet .prepared forbeing used in the inf,

vention to build up the screened sensitizedjsheet.

Fig. 4 is a sectional View of acompletesensitized.' sheet on the drum surface according vt.o the i vention.

Fig..5 is a sectional View of a completesenstized sheet produced by thesurfaceof Fig. 2, after'hav` ing been taken from thedrum. f

Figs. 6 and` 8 are perspectiveviews` showing diierent matrices.

Figs. 7 and 9 are perspectiveviews showing the resulting screen patterns.

Figs. l0 and-l1 are sectionaldiagramsofider vices suitable for de-screening a. sensitive. sheet. Referring now tofFigs. land 2", I indicates-a rotating drum having a metal surface in which are formed a seriesvof. grooves 2; The drum'l as it rotates dips intoa trough 3 .containing a solution l soA thatthesurface of. the drum onleavingj-V the trough Sis Vcoated witha filmof.the.soluti'ciri.l

As thedrum continues torotatathel film issfub'- jected to the ydrying actionf'offaheater 5 'and"the.

film Vdries intoathin skin indicated at 6in Fie. having a .continuous series. of cavities.

the roller 'Iv the covering substance. whichl'has been applied tothe' surface of the drum issub-v jected to theaction'of a doctor knife Band thence! to the drying action of another heater Slg'llie@ covering substance which.fills the cavitiesvin' the skin Sis indicated at. l0. in Fig. 4 andV now-fthe.,

drum layerfhasapplied toit. the sensitized Ina.-V This. is., carried outby'means. of, a. strip f of cellulose acetate film i4 (Eig. 3),..whichftr'avels overrollersfll and 'I lY with. the sensitized^sur1`l facel i 5 innermost, andsliortlyprior toy entering into contactwith'thedrum lv the sensitizedst'rip. 'of .liilrrrY lflf hasY applied to it a coatinglfl'l" This. coating.V consists ,of an adhesive'.

so as to unite Vthe sensitized stripV to thecovered skin S-l. By means' of aheater l2, heat -ifsfapf'f plied to the surface of the drum, causing thefskinV B-I 0 Vto adhere to the adhesivev I 6 on the filmstrip terial.

(Fig. 3)..

and the multi-layered composite strip now leaves v wheni the skin '6 reaches a pointloppositetherolleii the drum .and'fpas'ses `away. over; the roller =21I I':-; in thekdirection ofthe arrows' I3. -Thusatcomplete sensitized'. sheet as represented'inFig." is. ober;

vInFig. 10,` '100 .is a. roller on which a rollerz22; exercises" av certain lamount 4of --pressu're'f..23-is; aframe 'parallel to theroller I I00 andz extending". over Sits entire-length.: .24 is a'roll off-f adhesiye-V paper. :When the apparatus is in-operation,the, adhesive-paper will move'inthe directionrof Hessing. over the roller I Dit has its, adhesive Side uppermost.; When a `sensitized sheetl v2I, suitable forthe npurpose and provided with a screen,

passed in" the same directionwith-.the screen, Side and l 22,it will unite with the adhesive paper at `directed downwardls ,between the rollers I00 the pointof passage between themsaid cylinders and together therewith proceed on its waytozthe/ edge 28 of the frame 23Here the adhesive paper makes a sharp turn downwards, while the sensitizedzsheet continues straight on.(as arule itlis stiif 'enough to do this); lllf their'degreeoffvadhesion tothe sensitized sheet .is smaller than their-adhesion to the adhesive surface, the covere:

inglscreen-portions will fadhereto the strip-and be' carriedalong on the latter; thismanner ther screen is removed from the sensitlz'ed'sheet. After. that, 'the latter can loe-subjected tothe :usualV aftertreatment, for example; inv the case-.ofsla' diazotype sheet, a.half-wet1 or dry-developing process. The deescreeningv apparatus .can` be coupled with a developing-apparatus.

Referring to the mod i'cat'ion as shown in Fig. 11, the lowerr'nost cylinder |00 is replaced -bya perforated cylinder35, inwhich is la stationary hollow cylinder 29 having an interiorp'artition 30- and slots`v 3'I andV 32,- extending-:overtl'ie'entirel length of the cylinder. On"oneside f -thepartiLV tion 30', there is a chamber'- 331a'n'd `on the other si'dea-chamber 34. These chambers are closed at one -'end, the other end being connected to an ai-r'puir1p,rv pumping the air l from 33 to 34. The editi-consequently streams in through 3| andvout'` again through 32'. Around this cylinder 20 is the perforated cylinder 35v which is mounted so that it rotates in the direction of the arrow. The cylinder 22 exerts pressureon 35. The outer surface,Y of 35 may beadhesive.r After an image hasfbeen'formed, thefscreened sensitized sheet 2l with the screen. skin directed downwards, is-

introduced between cylinder' 22 and cylinder 35,v

moves in the direction of the arrow', isv caught! byjthe suction at 3| and stuck on the surface of 35',k afterwhich it is lightly loosened' near '38' by means 'of a point or a narrow'blade-shaped objectA 36 and conducted farther k-(e.-' gx by` hand) 'i in the direction of the arrow. When-theIadhey` sion of the screen skin to the wall 35fat`pointl Figs; lela' skin beffcuirmedy 3Q 0.8 phloroglucinol lose film I 4, 'Whose thicknessis `in yaccordance with1,80 g. perm.2 issuperflcially saponifedand.,Y

.2% thioure'af 1 10% ethyl alcohol 4 s y A Y y As described above the sensitizedfllrn I4 with s its `sensitized side towards the cylinder I is united by. means-of anladhesive layer of rubber latex I6 s to Itherskin 6, saidskin and filling I0 .constir tuting the covering screen. I. *l y The, product thus obtained vis* :shown: in section-'1 in Fig. 5.` In practice the adhesive layerI negligibly thin.A 'It forms ytogether with theJayery,

'6. and theV filling I0. `(in closed cavities). a skin :Theproductislaid with its lowerA side on an. originalV and is exposed through vIi. Thereis obf tained a screen reilexcopy; which after stripping l off the skin consisting of -6,.I0 and I5, is developed by lapplying .to layer I 5 a Aiilm y of developer l com: posed as follows: 1 y

0.8% resorcinol 3% sodium carbonate 6% sodium thiosulphate 2% thiourea 1% trhodanide of. potassium 0.2% of the sodium salt ofisopropylnaphthalene y .sulphonic acid y Evagample 2 chloro44-dimethylamino-benzene, and thezcovering substance applied at '7 (Fig: 2) consists of a paste of -carbo'n black in water mixed with ai little alcohol and gum arabic. This again. produces a screened diazotype sheet orfllmof the type shown in section in Fig. 5, with a screen-patternA onlyfcon'sisting of substantially light impervious covering portions (substantially opaque areas), adjacent to portionspfervious to light (substanf tiallyvtransparent Sareasly without intermediate v graded transitions and suitable for screen-reneetography. The 'covering portions occupy approxi-1i mately of the surface and the period ofthe Since the layer I6 is extremely thin `v(mucl'thinner4 than proportionally drawn in Fig. 5) there isand "thisis of great vimp'ortancelin screen-ree'y flectography-close contact betweenthe portions Y10 (in closed ycavitiesland the sensitized layer I5.

Afterexposure in kco'ntacijfwithan original as in-'screen-relectography, the screen skin I--I0- I6 -is stripped off and the sheet is developed. The ree'x copy obtained is vsuitable for being're- Example 3 An'acetyl cellulose lm of 70 g. per m.2 is soaked alittleon onesurface by means of acetone. This surface is pressed against a relief mould as shown in Fig. (iw-ith depressions having the following di,- l mensions: 30 X 30a, depth 15M, period 80a. The surface of the lm is thus formed with the pattern of Fig. 7. "It is saponied and sensitized as in Example 1. The cavities 20. are lled upwith egcoarz/ic-a nernormal1inscreen-reflectography, and treatedA by V,brushing-.With'the same developer as in. Exf ample 1. The carbonl'black. constituting the screen is thus removed from the open cavitiesbetween the parts 2|, While the image appears at the same time. Instead of using carbon vrb'lfack, other covering substances, such as barite`, titandioxide or others'may befemployed. 1r.

If'y insteadVoff a"paste of carbon black and tolene'for the covering' substance, a 'past'e'con` sstingofflnely divided thiourea and toluene or ground thiourea-powder is used, Athen" it' isVV not necessaryto@ brushjf with the developer and it is sui'cient Ito Aapplyathin (inthis caseinot too' thimlayer lici-developer. The thiourea dissolves by this treatment, thus becomingL transparent, and does -not again become av covering substance in drying. A sufficiently fine division of thiourea can be' obtained bygr-inding,v e. g. with toluene inea 'collod-'millg In asimilar way itis pos-r sible', n )fcourseftjo apply'numerous other soluble' substances suchas urea; thiourea, potassium oxalat'e as the covering substance within the'spirit of the invention. 'f Y l Example 4 In the manner described in Example Y 3 a screened sensitized sheet is made ona'relief as shown in Fig. 8 and having the following dimen-` sions: width of the channels c, depth 8c,period 80a. In this Ymanner a-relief -formati`on-islobtained Vas shown inl Fig; 9.* ThegsidecarryingV the carbon black screen, it is now 'treated With'a solution of 4% acetyl cellulose in acetone, after which it is dried. The covering screen portions thereby acquire such a degree of cohesion that.

-byipressing them; afterv exposure, ont@ an adhesive layer of1latex,.they remainy rmly affixed4 tot theV latter. Thus, uponY separating'the sheet from the adhesive; layer, thej screen v`is removed from the sheet. j

It isfalso possible to proceed inthe-following,Y way; The; saponiiied sensitized sheet provided withthe relief;` is treated with a 3%jsolutionfoi; acetyl/cellulosein acetone, passedunder a-doctorV knife and..v dried. Thereuponaccerding to the.,v method-of LExample 3, carbon black isintroduced, into thecavities by rubbing into them a paste consisting'of 10.1% of' carbon'fblackA and 0.8%V oi colophony in'rtoluene, after which the sheet isv dried and passed :under a'doctoring or Wiping--o' device. ;The-.,treatrnent is subsequently repeatedA withfa 3% solution off acetyl cellulose in acetone;Y and thesheet again passed under the doctoring` or ;wipingof. device and dried. When the screened ,sheet thus obtained' is'imrnersed: in the developer 'of Exam-piel, tofwhich a slight amount of acetone ispreferably added, thev coveringscreen portions Wil'lybecomezdetached land by` rubbing the'surface lightly, forjinstance vvithfa.A bit of Wadding, can be removed from the cavities,... without, to any appreciable extent, impurifying the liquid by loose carbon black particles. In thisway considerably cleaner Workisobtained than When Working. Without Jtheftreatments: .with acetylv cellulose. Instead. r off acetyl L cellulose'V also substances .like ethyl cel1ulos`ec'anLbe:usedlA j Example 5. y n, t, 4, The relief .of sensitized sheet as. described van 0.8%y colophony solutionin toluene.

ofi214.6.z-trinitrotoluene` is.` dissolvedV and. 10% of sequently dried' and'. passed'under a. doctorinefk or 1 Instead of 2.4.6-trinitrojto1u-g. 1 ene..-it`is possible to use::-1.3-.5-trinitro` benzene,

l-dinitrobenzene, -naphthalene and thelilze wiping-off device.

By; immersi'ngfthe 'sheet in` the developer of` Ex-` amplelwandrubbingit gently, the coveringl screen por-tionszwillk bei removed: satisfactorily in large;l

piecesi.. Itz'is also-possible toxrernoyeithe1screen byjmear'isr'of` anadhesive2 layer'.- The carbon blackl from; Schlutzs Farbstoltabellen 1931, which dyer`r` stuifdissolvesintoluene: Y: s

The relief.l of a sensitized sheet 1 as described inl Example y 4` filled with toluene; containing' 35 of 2.4.6*-t'rinitrotoluene and 4%Y ofV carbony black, passed-under a doctoringor wipingof "des vice anddried'. l Thisgtreatrncnt-'is repeated with a 'similarpasta but? n'ovvwi'th the-addition of 2%1 ofVV rubber. y shceifcan be de-screened bymeafns offan adhesive; layer having anadhef sive-power yslightly smaller than in the case of* Example '5.'vv v y Example 7V There-:relief of;v a.' sensitized sheet as describedin Examplee isy treated with `a. paste of bariumsulphat'e pigmentedfwith sulphide of1lead'in benzene.;

in which 21%; oflrubber dissolved; passed under.

a zdcctorf knife .andV dried.l The screen can very` Well' be.l removed with the iaidof anadhesive layer;

. :i www Y Inv the manner described in- 'Example 3` a .sensi-r tiZedsheet, screened-With carbon black is madev on-awrelieiaccording to. Figl having dimensions like: those speci-ned in Example-'4.f- It isv Subsc-- quently treatedion` the screen side with a soluton of 20 of-Canadabalsam in toluene, passedv under aV doctor; knifev and dried. Thesheetcan be -de-screenedby means-of an'adhesive layer.- Ifthe ,Canada balsam `had been-applied to the cavities `together- .withI thev carbonl black; the rel mo'val` of 'th-e3 covering Ascreenv portions would have been'- much more dicult: or even' entirelyl impracticable;

Y y v Example 9 An-acetyl .cellulose lm ofvv 30r g. per m? is softcned ,a littie'on'onesurface by meansof acetone. This surface is pressed'aga'inst` a relief as shown inxlig; 8,' having; the*Y dimensions indicated" in Example 4. The surface off the lm will now.

20%i4 ethyl-f: alcoholI mea-nsv ofvi'pa-stirrigand rpassing` underta, doctoringlor wiping-oli device, the cavities-of the `reliefforniatiorrare?novv lled with a paste con-- sisting Vof-nely divided sulphate ofbarium and drying, a thin layer yis applied by means of a 4% solution of acetyl cellulose in acetone, after which'the sheet is drieda'gain.l 1 The thus After screened' isf subjected to' exposure' on `top'of'an -original y"accordingf to 4diazotype'l reflectography land subsequently its screened side, in an apparatus acoordingto Fig.A .10, is Yguided over an adhesive ribbon, the adhesive surface of which con- -sists ofv dried rubber. latex.' `The nlm thus 'de- 'screened is developed iny ammonia-vapour and lcan 'be used for re-copying onpositive diazotypelayers.

vWhat we" claim is: Y A1.`A sheet suitable for reectography in the positive diazotype'process comprising as a unit 1a' transparent support,:a .light sensitive diazo layer Vand a screen the pattern of which is in the immediate vicinity of the sensitive diazo layer and consists onlyfof portions substantially impervious Ato light-to which the diazov layer is sensitive, interspersed, with portions that are "substantially f perv'ou's to this light; Without intermediate'g'raded transitions, the substantially impervious portions formed' by deposits in cav- 'iti'es'present-in the sheet, said deposits comprising particles constitutingy substance substantially opaque' to said light in such a state of cohesion rthat the substantially imperviousv portions are removable from the cavities substantially' asin- 'tegral'bodiea yand a thin transparent skin interconnecting adjacent deposits as -Va collective unit removable from the sheet.y a y 2, A sheet suitable' ior'reiiectographynin the positive diazotype process comprisingas a unit a'transparent support, a light sensitive diazo v layer and a` screen the ,pattern of which is in the immediate vicinity of the sensitive Adiazo layer and consists only of portions substantiallyr impervious to light to which the diazo layer is sensitive, jinterspersed with portions that are substantially pervious to this light, Without interinediate graded transitions, the substantially impervious portions formed by deposits in cavlitiespresent in the sheet, said deposits comprising particles constituting substance substantially .an inlaid light screen, and a thin skin of cel.-

lulosicmaterial transparent 'to said light over.-

lying the elevations osaidlayer and united.

with the tops of said bodies, said bodies moving "fromy said cavities "as partl of said skin upon stripping said skin from said sheet.

52` Ascreened diazotypeA sheetmaterial as described; in claiml, said cavities intercommunveatingaround said elevations 7and the opaque `bodies therein being integrally interconnected.

6.l A screeneddiazotype sheetmaterial as described in claim 3, said bodiesbeing deposits of a composition of a finely divided pigment and ka binder therefor. l

y'7 A screened f diazotype sheet 'material as described ingclaim 3, said bodies being deposits of av composition Aof lcarbon black Aand a binder therefor. f v Y. 8. A. screened diazotype sheet material for positive reectography, comprising in a unitary flexible sheetpstructure a sheet of a cellulose `ester composition,r said sheet being supercially saponied and a saponifled side thereof being formed as Aa depthrelief and` carryingla lightsensitivediazo layer so that said layer presents a myriad of rminute cavities interspersed with elevations, said sheet being transparent to the 'light to Vwhich said layer is sensitive, said cavities beingv filled with ldeposits opaque to said light constituting an inlaid light screen, and a thin skin of a cellulosic material overlying said elevations and united with said deposits, said said .light being inlaid over said nlm's and filling -said cavities substantially to .the,.1evel of'said elevations to constitute a light .'screen,v and Va thinfskin of a :cellulosic material transparent to said light overlying' said elevations and united With said bodies. v

145A screened diazotype sheet materiall as described inA claim .13, `said cavities intercommu- --possess substantially Vcomplete covering power therefor, theflexible Asheet structure comprising a fmyriad of :minute cavities distributed over said-sensitizedide and said screen pattern connicating around the .respective elevations and the respective thin lm portions therein, -also the Yrespective. opaque bodies therein, Y. being integrally interconnected.

15.-'A method of producing a screened ndiazotype sheet material for positive vreflectogra'phy Which comprisesproviding a transparentsheet of a cellulose estercomposition in a plastic state over one side, impressing said plastici'side with a depth relief member having a myriad of'minute cavities therein interspersedv with minute `elevations so as to form a compiementary myria-:lcf elevations and cavities over said side, supercially saponifying the impressed side, then applying alight-sensitive diazo layerthereover sotha't said layer presents a corresponding `myriad .of elevations and cavities, and applying avcohesive opaque composition over said side-sofas-toll the cavities of said "layer with deposits fof `such composition and wiping such composition 'from the elevations of said `layer to render the elev ations light pervious.

y 16. A method as described in claim 15,'landV thereafter applying a solutionof a transparent cellulosic composition oversaid side so as fto form a thin skin'of such composition overlying the eleyations and united with the deposits in thecavities of said layer.

v'17. A method as described' in `claim` 15, and applying to said side before'` applying saidopaque composition a solution of a cellulosic composition so as to form thin films thereof in the bottomsof the cavities of said layer.

'18.111 amethod as described inVY claim '15, applying to said side before applying said opaque composition a solution of ya cellulose ester composition so `as to form thin nlms thereof in the bottoms of the cavities of said layer, and after applying and wiping said opaque' composition applying a solution of arcellulose .ester composition over said side so' as to form athin strippable skin overlying said 'elevations andunited with said deposits.

119. SensitizedV sheet material foriproducing positive diazotypes by reflectography comprising, in a unitary flexible sheet structure, a Yflexible support transparent to the `exposing light, `a

light-sensitive diazo layer over aside thereof, and

alight screen the pattern of Which overlies and sisting1of portions .substantially opaque to said vlightrformed by deposits filling said cavities and interspersed with portions substantially transparent rto said light, WithoutV intermediate ygradated' transitions, Vthe .cavities holding said. 'deposits being formed .by ia skin 4transparent .-to lsaid light, :said skin surrounding Vsaid deposits and being vjoined firmlyxto saiddiazo` layer, yet strippable bodilyztherefrom to separatezt-he screen from other partsof--the sheet.

` 2l. Sensitized .sheet material for producing positive diazotypes by reflectography l comprising, in Va' unitary flexible Vsheet structure, a support transparent to the exposing '-light, a lightsensitive `diazo layer over a Vside thereof, and yalight screen` thepattern of which covers the diazo layer and consists only Vof portions ysubstantially opaque rtosaid lightinterspersed with portions substantially transparent thereto, Without intermediate gradated transitions, the sensi- .tive diazo layer comprising a myriad of minute at least nearly contacts the diazo layer to possess f substantially complete covering power therefor, the "iiexible sheet structure comprising alayer adheredto saidsupport and extending over its sensitized side and forming a myriadof vminute Y cavities distributed thereover and Vsaid screen pattern consisting of portions substantially opaque to said lightformed'by deposits iilling said cavities therein distributed evenly over said .sensitized side, said opaque vportions being formedlby deposits filling saidcavites.L

Y 22. `.Sensitized ,sheet material for producing positive diazotypes by reiiectography comprising, in a unitary flexible sheet structure, a support transparent to the exposinglight, la light-sensitive diazo layer overa side thereof, andalight screen the pattern of which i covers the diazo layer and consists only of portions substantially opaque to said light interspersed with portions substantially transparent-thereto, without intermediategradated transitions, the sensitive diazo layer comprising a myriad of minute cavities therein distributedrevenly over said sensitized side, ysaid opaque portions being formed by deposits illing said cavities, and being soluble'in a liquid useful for developing said diazo layer,

whereby the screen pattern is readily removable from the material after `an exposure of Vthe material. Y Y

Y 23. sensitized sheetmaterial for producing positive diazotypes by reflectography comprising, in a unitary iiexible sheetstructure, a support transparent to thev exposing light, la light-sensitive diazo layer over a y-sidethereol and a light screen the patternof YWhich covers the diazo layer and'consists'only ofportions substantially opaque to saidlight interspersedY with portions substantially transparent thereto, Without intermediate gradated transitions, the sensitive diazo layer comprising va ymyriad of minute cavities thereinjdistributed evenly lover saidl sensitized side, said opaque portions being formed by deposits lling said cavities, and comprising nnely divided particles `in a state of cohesion such that the deposits are removable bodily from their respective cavities by a pulling force. I

y 24. Sensitized sheet material for producing positive diazotypes by reiiectography comprising, ina unitary flexible sheet structure, asupport transparent to'the exposing light, a lightsensitive diazo layer over a side thereof, and a light screen the pattern of which coversthe diazo layer and consists only of portions substantially opaque to said light interspersed With portions substantially transparent thereto, Without intermediate gradated transitions, the sensitive diazo layer comprising a myriad of minute cavities therein distributed evenly over said sensitized side, said opaque portions being formed by depositsl filling said cavities, said deposits each comprising a plurality of layers of which at least one is opaque to said light and which cohere to each other under a pulling force more strongly than the bottom layer adheres to the bottom of its cavities.

25. sensitized sheet material `for producing positive diazotypes byk reiiectography comprising, in a unitary flexible sheet structure, a flexible support transparent to the exposing light, a lightsensitive diazo layer over a side thereof, and a light screen the pattern of which overlies and at least nearly contacts the diazo layer to possess substantially complete covering powertherefor, the flexible sheet structure comprising a myriad of minute cavities distributed over said sensitized side and said screen pattern consisting of portions substantially opaque to said light formed by deposits dilling'said cavities and interspersed with portions substantially transparent to said light, Without intermediate gradated transitions, the adjacent deposits being interconnected cohesively by means distinct from and strippable bodily from yet joined firmly to the diazo layer, whereby the opaque deposits are readily separable from other parts of the sheet structure.

26. A screened sensitized sheet material for producing positive diazotypes by reiiectography comprising, in a unitary flexible sheet structure, a flexible support of cellulosic material carrying a light-sensitive diazo layer on one side and trans- 14 parent to the light to which said layer is sensitive, said support being formed with a depth relief impression over said one side presenting a myriad of minute cavities interspersed with elevations, said cavities being filled by bodies opaque to said light to constitute an inlaid light screen, the respective bodies and elevations forming a surface parallel to the other` side of said support and composed of myriads of distinct areas, respectively, opaque and transparent to said light, without intermediate gradated transitions.

WILLEM MARIE BUSKES. THEODORUS PETRUS WILHELMUS p l SANDERS. MATHEUS MARINUS PAULUS VALLEN.V KAREL MARIA HUTGENS.

REFERENCES CITED The following references are of record in the file of thisv patent:

UNITED STATES PATENTS Number Name Date 492,333 Levy fFeb. 21, 1893 2,026,292 Van der Grinten Dec. 31, 1935 2,051,585 Van der Grinten Aug. 18, 1936 2,283,715 Yanes May 1'9, 1942 2,303,395 Schultz et al Dec. 1, 1942 FOREIGN PATENTS Number Country Date 15,994 Great Britain 1901 20,046 Great Britain 1909 229,552 Germany Dec. 24, 1910 

1. A SHEET SUITABLE FOR REFLECTOGRAPHY IN THE POSITIVE DIAZOTYPE PROCESS COMPRISING AS A UNIT A TRANSPARENT SUPPORT, A LIGHT SENSITIVE DIAZO LAYER AND A SCREEN THE PATTERN OF WHICH IS IN THE IMMEDIATE VINICINITY OF THE SENSITIVE DIAZO IMPERVIOUS TO LIGHT TO WHICH THE DIAZO LAYER IS SENSITIVE, INTERSPERSED WITH PORTIONS THAT ARE SUBSTANTIALLY PERVIOUS TO THIS LIGHT, WITHOUT INTERMEDIATE GRADED TRANSITIONS, THE SUBSTANTIALLY INPERVIOUS PORTIONS FORMED BY DEPOSITS IN CAVITIES PRESENT IN THE SHEET, SAID DEOSITS COMPRISING PARTICLES CONSITUTING SUBSTANTCE SUBSTANTIALLY OPAQUE TO SAID LIGHT IN SUCH A STATE OF COHESION THAT THE SUBSTANTIALLY IMPERVIOUS PORTIONS ARE REMOVABLE FROM THE CAVITIES SUBSTANTIALLY AS IN TERGRAL BODIES, AND A THIN TRASPARENT SKIN INTERCONNECTING ADJACENT DEPOSITS AS A COLLECTIVE UNIT REMOVABLE FROM THE SHEET. 